«Invalid state change requested» on `/onestepcheckout/`

{
    "channel": "main",
    "context": {
        "exception": {}
    },
    "datetime": {
        "date": "2023-07-27 11:27:36.476972",
        "timezone_type": 3,
        "timezone": "UTC"
    },
    "level": 500,
    "level_name": "CRITICAL",
    "Mage2.PRO": {
        "IP Address": "136.228.225.124",
        "mage2pro/core": "9.5.0",
        "Magento": "2.3.7-p4",
        "PHP": "7.4.33",
        "Post": [],
        "Referer": "https://www.tradefurniturecompany.co.uk/onestepcheckout/",
        "Request Method": "POST",
        "URL": "https://www.tradefurniturecompany.co.uk/rest/default/V1/guest-carts/C1MryvpOXltz1QOQ0fYIlcjeiEOBGHFA/shipping-information",
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36 Edg/115.0.1901.183"
    },
    "message": "Invalid state change requested"
}
Location:    vendor/monolog/monolog/src/Monolog/Logger.php:344
Callee:      Df\Framework\Log\Dispatcher::handle
*****************1******************
Location:    vendor/magento/framework/Logger/Monolog.php:48
Callee:      Monolog\Logger::addRecord
*****************2******************
Location:    vendor/monolog/monolog/src/Monolog/Logger.php:740
Callee:      Magento\Framework\Logger\Monolog::addRecord
*****************3******************
Location:    vendor/magento/module-checkout/Model/ShippingInformationManagement.php:186
Callee:      Monolog\Logger::critical
*****************4******************
Location:    vendor/magento/framework/Interception/Interceptor.php:58
Callee:      Magento\Checkout\Model\ShippingInformationManagement::saveAddressInformation
*****************5******************
Location:    vendor/magento/framework/Interception/Interceptor.php:138
Callee:      Magento\Checkout\Model\ShippingInformationManagement::___callParent
*****************6******************
Location:    vendor/magento/framework/Interception/Interceptor.php:153
Callee:      Magento\Checkout\Model\ShippingInformationManagement::Magento\Framework\Interception\{closure}
*****************7******************
Location:    generated/code/Magento/Checkout/Model/ShippingInformationManagement/Interceptor.php:26
Callee:      Magento\Checkout\Model\ShippingInformationManagement::___callPlugins
*****************8******************
Location:    vendor/magento/module-checkout/Model/GuestShippingInformationManagement.php:43
Callee:      Magento\Checkout\Model\ShippingInformationManagement::saveAddressInformation
*****************9******************
Location:    vendor/magento/framework/Interception/Interceptor.php:58
Callee:      Magento\Checkout\Model\GuestShippingInformationManagement::saveAddressInformation
*****************10*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:138
Callee:      Magento\Checkout\Model\GuestShippingInformationManagement::___callParent
*****************11*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:153
Callee:      Magento\Checkout\Model\GuestShippingInformationManagement::Magento\Framework\Interception\{closure}
*****************12*****************
Location:    generated/code/Magento/Checkout/Model/GuestShippingInformationManagement/Interceptor.php:26
Callee:      Magento\Checkout\Model\GuestShippingInformationManagement::___callPlugins
*****************13*****************
Location:    :
Callee:      Magento\Checkout\Model\GuestShippingInformationManagement::saveAddressInformation
*****************14*****************
Location:    vendor/magento/module-webapi/Controller/Rest/SynchronousRequestProcessor.php:95
Callee:      call_user_func_array
*****************15*****************
Location:    vendor/magento/module-webapi/Controller/Rest.php:188
Callee:      Magento\Webapi\Controller\Rest\SynchronousRequestProcessor::process
*****************16*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:58
Callee:      Magento\Webapi\Controller\Rest::dispatch
*****************17*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:138
Callee:      Magento\Webapi\Controller\Rest::___callParent
*****************18*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:153
Callee:      Magento\Webapi\Controller\Rest::Magento\Framework\Interception\{closure}
*****************19*****************
Location:    generated/code/Magento/Webapi/Controller/Rest/Interceptor.php:26
Callee:      Magento\Webapi\Controller\Rest::___callPlugins
*****************20*****************
Location:    vendor/magento/framework/App/Http.php:116
Callee:      Magento\Webapi\Controller\Rest::dispatch
*****************21*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:58
Callee:      Magento\Framework\App\Http::launch
*****************22*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:138
Callee:      Magento\Framework\App\Http::___callParent
*****************23*****************
Location:    vendor/mage2pro/core/Framework/Plugin/App/Http.php:10
Callee:      Magento\Framework\App\Http::Magento\Framework\Interception\{closure}
*****************24*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:135
Callee:      Df\Framework\Plugin\App\Http::aroundLaunch
*****************25*****************
Location:    vendor/magento/framework/Interception/Interceptor.php:153
Callee:      Magento\Framework\App\Http::Magento\Framework\Interception\{closure}
*****************26*****************
Location:    generated/code/Magento/Framework/App/Http/Interceptor.php:26
Callee:      Magento\Framework\App\Http::___callPlugins
*****************27*****************
Location:    vendor/magento/framework/App/Bootstrap.php:261
Callee:      Magento\Framework\App\Http::launch
*****************28*****************
Location:    pub/index.php:40
Callee:      Magento\Framework\App\Bootstrap::run
tradefurniturecompany / site

«Invalid state change requested» on `/onestepcheckout/` #271
